Have you turned on the option to allow forum subscriptions? Components > Subscriptions admin panel.

You may also need to visit the permissions to set which user groups/permission sets you wish to allow to use this.

Everything seems to be enabled in both sections. “Allow members to subscribe to forums in addition to topics” in the former and “Can subscribe to forums” in the latter.

OK – next question would be what SP theme are you using?

Looks like tbtheme

Ah wait, that’s clearly had some customization, based on the Default theme.

I swapped back to Default and still do not see buttons to subscribe to an entire forum.

You will need to add it to your custom theme. There is an explanation of the code and an example here in our Codex:

https://simple-press.com/documentation/codex/plugins/our-plugins/available-plugins/subscriptions/#sp_SubscriptionsSubscribeForumButton

This will need to go in the spForumView.php template. Normally it would appear beside the add topic button so go down and find the block of code named the pageLinks section. By default and with the addition of the forum subscribe button, the code should now like:

# Start the 'pagelinks' section
 # ----------------------------------------------------------------------
 sp_SectionStart('tagClass=spPlainSection', 'pageLinks');
    sp_TopicNewButton('tagId=spTopicNewButtonBottom&tagClass=spButton spRight', __sp('Add Topic'), __sp('Start a new topic'), __sp('This forum is locked'), __sp('No permission to start topics'));
     sp_SubscriptionsSubscribeForumButton('tagClass=spSubscriptionsSubscribeForumButton spButton spRight', 'Subscribe', 'UnSubscribe','Subscribe to this forum', 'UnSubscribe from this forum');
     sp_TopicIndexPageLinks('', __sp('Page: '), __sp('Jump to page %PAGE% of topics'), __sp('Jump to page'));
     sp_InsertBreak();
 sp_SectionEnd('', 'pageLinks');

Making sure we’re on the same page – it isn’t included, out of the box, with the Default theme?

Apparently not. Unsure why but there are several tags that are not included by default.

Good enough.

Semi-related, if a user subscribes to a forum, are they automatically subscribed to all child forums (existing and created down the road)?

Not the case i am afraid. They will still need to choose to subscribe to specific forums to which they have access.

So subscribing to a forum just alerts you of new topics in that forum?

That is corrrct